1. Field of the Invention
The present invention relates to an air-cooled, reciprocating piston, internal combustion engine having at least one row of cylinders and individual cylinder heads arranged side-by-side, each row of cylinder heads being provided with lateral defectors adjacent the end cylinders thereof, and each cylinder head in each row including means such as bosses for accommodating attachment bolts. More particularly, the present invention relates to such internal combustion engines wherein each of the cylinder heads thereof has at least one inlet valve and one exhaust valve, the valve stems extending substantially parallel to the axis of the associated cylinder and being situated such that a plane passing therethrough lies at an acute angle to the longitudinal direction of the internal combustion engine, and wherein each cylinder head includes an intake duct located on a side thereof swept by cooling air (its inlet opening being located approximately centrally of the cylinder head), and an exhaust duct extending substantially perpendicularly to the exhaust air or exit side.
2. The Prior Art
An air-cooled, reciprocating piston, internal combustion engine of the foregoing type is available as commercial engine series 924 to 930 of the Tetra-Werke, Czechoslovakia, it being illustrated and described in the technical publication entitled, "Air Cooled Automobile Engines," by J. MacKerle, Frank'sche Verlagsbuchhandlung, Stuttgart, 1964, pages 171 to 173 and 524 to 528. The design of the cylinder heads and cooling ribs thereof is such that each cylinder head constitutes a cooling unit per se through which air flows in substantially straight lines. Thus, one cylinder head and its associated lateral deflectors forms merely a restriction for the flow of air to the other cylinder head. However, reciprocating piston, internal combustion engines with cylinder heads of this latter kind are suitable only for limited outputs, since the area of the exhaust ducts, in particular, and the areas between the exhaust duct and the cylinder barrel, cannot be adequately cooled. This is also due to the fact that the bosses for the cylinder head attachment bolts extend, in the crankcase, to the upper edge of the cylinder head.
It is therefore a main purpose of the present invention to improve the air-cooled, reciprocating piston, internal combustion engine in question, and the cylinder heads and cooling thereof, in such a manner such that higher outputs can be achieved, such that satisfactory guidance of the cooling air and satisfactory cooling of hot spots is achieved, and such that the production costs are favorable.